Various types of disposable absorbent articles such as disposable diapers, training pants, swim pants, incontinence articles, and the like, utilize a chassis incorporating an absorbent system and an elastomeric waistband. The waistband provides for enhanced fit, comfort to the wearer, and improved product performance.
Much attention has been paid in the art to development of various elastomeric waistband configurations. For example, U.S. Pat. No. 4,205,679 discloses various embodiments of a pull-on pant-like article having gathered elastic waistband portions. U.S. Pat. No. 4,639,949 describes a disposable absorbent garment having an improved elastic waistband with an elastic element joined in a stretched condition to a marginal portion of an exterior panel of the garment with a plurality of spaced bond points. U.S. Pat. No. 4,904,251 describes a disposable diaper having gathered elasticized front and back waistband portions. Tape fasteners are provided on back side flaps for fastening the front and back regions of the article together on a wearer. U.S. Pat. No. 5,676,661 similarly discloses a diaper configuration having elasticized waistband portions and tape members extending from the side margins of the back waist region. The tape members include a fastening strip, such as a hook-type material, that attaches to a corresponding landing pad material provided on the front waist region to secure the article to a wearer.
With a known commercial disposable diaper (the HUGGIES® brand from Kimberly-Clark Corp. of Neenah, Wis., USA) elasticity is provided to the back waistband by elastomeric strips bonded to side edges of the chassis at the waist region. A non-elastic material strip is bonded to the outboard end of the elastomeric strips, and a micro-hook material strip is laminated to this non-elastic material. For securing the diaper on a wearer, the hook material attaches to a piece of non-woven web material adhered to the outer cover at the front waist region. Thus, with this configuration, the chassis has generally non-elastomeric waistband portions, and the degree of elasticity provided around the waist of a wearer is a function of the elastomeric tab strips.
Conventional elastomeric waistband configurations may, however, be improved upon. For example, with diaper configurations wherein elastomeric waistband portions are defined at the longitudinal ends of the chassis by adhering elastic strands or strips in a tensioned condition to the liner material and/or outer cover, it is very difficult to accurately predict and control the elasticity of the respective portions under multiple wear conditions. As other materials are added or attached at the waistbands, such as containment flaps, the overall elastic modulus of the waistband changes. A change in the outer cover material or liner material will change the elastic modulus of the waistbands, and so forth. To accommodate for such variance, manufactures tend to use more elastic material than would otherwise be necessary. Unfortunately, the elastic materials are relatively expensive.
With the diaper configurations wherein the chassis waistband regions are non-elastomeric and elasticity is provided by elastomeric tab strips, the bonds between the elastomeric strips and chassis sides must be particularly strong to withstand the tensile forces exerted by the strips in use. The same concern applies to the bonds between the elastomeric strips and fastening strips. Many consumers believe that they must stretch the elastic tabs as much as possible in order to obtain a secure fit of the diaper. This results in significant tensile forces being exerted at the bond points. Tab tears at these locations is a common complaint with consumers. Adding additional length to the elastic strips would only add significant cost, may degrade fit and performance, and may impede attachment of both tabs along the front waist region of the chassis. Also, from a manufacturing standpoint, the process of forming the multi-component elastomeric tabs and bonding the tabs to the article chassis is material intensive and relatively complicated.
The present invention provides an improved elastic waistband configuration that may help alleviate deficiencies of current configurations.